Hay guys. By the looks of things there's been some debate on this product. Recently just buying a second car Nissan maxima with a vq35 engine same engine in the 350z been looking into mods there's a spacer kit for these cars witch no bullshit works and have been proven by about 20 different members on the maxima org site they defiantly gain a minimum of 10hp with no lose of power in the top end. The only thing different could be that this product by Nwp could be superior to others that are on the market. Plus I've noticed the bypass the throttle body coolant lines Aswell on this product witch I know on our 3rd gens we also have coolant lines going into our throttle body's. I know these would obviously help warm the car up but without super hot coolant running through the throttle body there's gotta be a definate drop in temprature. I'll post a link of the product. I'm just putting it out there cause I know every engines different. But our engines a v6 like these and are similar in ways. http://www.nwpengineering.com/Phenolic_Spacers.html

the colder the air is, the denser it is, the more atoms its made up of. Its the oxygen ones we want to make the boom with the fuel.
if the cylinder sucks in 1/2 litre of air at 20 degrees, it will have more oxygen atoms than 1/2 a litre of air at 60 degrees so will be able to burn a bit more fuel with it.
blocking the coolant lines to the TB and thermally spacing the intake will drop the intake temperature a bit, but because its mostly an un-shielded metal casting, it will pick up heat as the engine bay warms up anyway so after a bit of idling, it will probably be at the same temperature it would get to anyway. If you really want to cool intake temps, probably look into heat shielding on the intake and maybe some bonnet vents with the spacers and coolant re-routing.

If you bypass the coolant lines to your TB, your car won't idle well/at all.

Also, I'm making phenolic spacers for our intake manifolds and throttle bodies.

RPW charge 100 for lower intake manifold and 30 for the throttle body, which I think is a bit rich so I'm getting our autoCAD peeps at work to make me a design that I can send to Associated Gaskets.

If you bypass the coolant lines to your TB, your car won't idle well/at all.

Also, I'm making phenolic spacers for our intake manifolds and throttle bodies.

RPW charge 100 for lower intake manifold and 30 for the throttle body, which I think is a bit rich so I'm getting our autoCAD peeps at work to make me a design that I can send to Associated Gaskets.

Thatll be alright we need some real Dyno proof to see if these Work or not.

My opinion only but I figure they can show little if any gain in HP....the cooling effect the spacers partially provide in insulating the manifold on the air passing through the manifold would be minimal. I'd like to see a authoritive test as well.

I fitted an RPW "thermoblock" intake plenum gasket (phenolic spacer) to my 380 about 18 months ago.
I also bought and fitted some fibre washers on the plenum bolts.
As far as I can tell it made SFA difference to the temp of the intake plenum or intake air temps, and I probably wasted my time & money.
I have an UltraGauge plug in multifunction thingamebob which reads and displays a number of engine related parameters, and one of those is intake air temp.
On warmish days it reckons my intake temps can get up to 50 degrees Centigrade, and even on cool days the intake temp climbs pretty fast as the engine warms up.

KJ.

Two points to make here:
(1) I bet the factory engineers experimented with such heat barriers too. If they are not there ex factory it's probably because they do SFA.
(2) The engine bay is awash with hot air from the radiator. Any heat barrier in the intake system would be nullified by this effect. Ducting this air away from the engine would be of most benefit, if it was possible. You might have noticed there is one for the battery, so it stays cool.

Personally i don't believe intake temps make that much difference to the average magna anyway..

I have a theory that not much heat is transferred to the intake air from the manifold.

My reasoning is that the engine is 3.5L swept volume. It only has 3 intakes per revolution, so 1.75L.
at 80% efficiency, this means about 1.4L of air goes into the intake each RPM.
At an idle of 800 rpm, that's over 1100L per minute or almost 19L per second.

If you heat up a metal pipe to 80C and blow 1000+L per minute of air through it, I'd be surprised if the air increased by 1C in temperature. I might be wrong though.

You increase revs to a cruising speed of 2000 rpm and you're getting close to 50L per second or 2800L per minute. That air is going to absorb very little of the heat, IMO.

Never mind a power run between 4000 and 6000rpm where average is 7000L per minute or 120L per second.

So I think phenolic spacers and the like get shot down as BS too many times because I'm dubious that the intake temps will increase by much while sending 50L of air per second through the intake manifold.

However, if it only costs $30 and it reduces air intake temp by 1C, that's supposed to be good for 0.3 hp (3C cooler air =1hp gain apparently) - that's $100 / hp - not too bad really - a full exhaust is often quoted as being good for about 10hp and that can cost $1k which is the same cost per hp. Just don't pay hundreds of $ for any spacers.

These are just my ideas on this this old nugget though. I'd be very happy to see dyno or even scientific tests.
Measuring air temp in front of and out of a heated bit of pipe shouldn't be too hard.

I turned to one of my favourite sources, autospeed.com.au, and only found a reprinted article that read more like an advertisement. It did show 20C temp reduction on the manifold, but intake air temp wasn't measured.

Cheers, Graham.

Dude the air nowhere near flows that quick. If it did it would suck your hand in.

A turbo running 14 psi has basically twice as much air going in, and if it can do this: http://www.youtube.com/watch?v=AbXX-9eB7PI , then there must be a huge air flow rate, so even the Magna with nearly twice the engine capacity, but no turbo, must still have a respectable air flow rate.

OK, I know, just kidding. :)

But seriously, if a fish tank's pump can flow 200L of water per minute, why aren't our engines flowing 1000+L of air per minute - a combustion engine is just an air pump and a 3.5L V6 is not a small engine.

If my calculations are right, and there is that much air flowing, it sounds like you'd agree with me that not much heat transfer must be happening... :)

back to being serious, does anyone have an intake manifold lying around that they can heat up, point a hair dryer into (on cold, not hot) and measure air temp before and after the manifold to see how much heat transfer occurs?

You'll find those spacers do SFA!

You'll find those spacers do SFA!

...except lighten your wallet lol

These have been proven many times to be BS

For starters, look at the kits here that were designed to heat up the fuel rail but then you also used these spacers on your manifold and tb and removed the coolany fast idle hoses

Is like getting a chest freezer, filling it up with ice cream, unplugging it and then putting it on your back lawn on a 40 deg day

The air does flow very fast especially at any decent throttle opening and lets face it, dont you think if these were such wizz bang things for a whole 10hp that these would not be on every race, rally and performance car out there?????

Is just another way the scammers are finding a way to make money from people who thing that hp will come cheap

if 10hp came that cheap it wouldnt cost $500,000 to build a v8 supercar hahaha